Full text of Habakkuk 1:13: "You are of purer eyes than to behold evil, and cannot look on wickedness. Why do You look on those who deal treacherously, and hold your tongue when the wicked devours a person more righteous than he?"

It is clear from this that the prophet is comparing his own preconceptions of God's nature and behaviour with the rather different way God was actually operating, and the prophet is finding it puzzling, and hard to come to terms with it. see "Sadaq" for the Hebrew understanding of God's justice.